Laser cutter class

This page is the overview for the laser cutter class. The class is a project-based introduction to the software and hardware of the laser cutter, intended to teach participants in the class everything they need to know in order to use the laser cutter. We assume no prior knowledge of the software involved, only general knowledge of how to use a computer.

This class is broken into three main parts: part 1 deals with the design of the laser cut object using Inkscape, part 2 deals with the use of the laser cutter software, and part 3 deals with the operation of the machine itself.

This page is currently a work in progress, and should be used right now only for planning purposes, not as an actual resource for learning yet. When this message goes away, this page is considered usable as a learning resource.

Project Overview

In this project, we will create a laser cutter merit badge that employs many standard techniques in laser cutter design. This won't be a complete, in depth overview of the laser cutter and everything it can do. Instead, you'll learn a variety of standard techniques, along with the processes required to make use of them on the laser cutter, so that you become comfortable with the machine. These techniques include some basic design skills, preprocessing, vector cutting, vector engraving, press fit design, cut order optimization, and the general control of the machine. You will not learn laser safety: you must go through a separate training session for this. Please see the Laser Manual for more information about laser safety training.

This class has one suggested prerequisite, namely the class on design software, which will give you a more complete understanding of Inkscape than is provided here. While the prerequisite is not absolutely required, it's suggested because it helps you understand the software at a more general and fundamental level than we teach in this class.

Part 1: Design using Inkscape

In this part of the project, we will design the merit badge, both the physical aspects and its realization in software. There are therefore 2 main steps to perform here. The first step is to sketch out and decide on the overall design and dimensions, the second is to translate this into a precise sketch in Inkscape. This particular merit badge will be made of acrylic, but the steps described below work for pretty much any material you can cut on the laser cutter, provided it has sufficient thickness.

Rough Sketch

The merit badge we'll make will be based on the Noisebridge logo, as sketched below. We'll have an inset central Noisebridge logo out of black acrylic, and the rest out of blue acrylic. The outer portion of the logo will be engraved, as will the text.

Precise Sketch / Inkscape

We can get the Noisebridge logo in SVG format from the identity page. The direct link to the SVG file is https://noisebridge.net/wiki/File:Noisebridge_logo_not_by_idiots_for_cnc.svg. We'll open the logo in Inkscape and make some changes. Make sure to resize the canvas and save it as a new file. It's also useful to set up some grids. Millimeter units are generally the most useful.

Before we go any further, it'll be useful to resize the logo to be 60mm in both dimensions. This will make it easier to align things later. We'll select everything (control-A) and then set the size in the toolbar. Make sure the units are millimeters.

Now on to the real editing. First, let's get rid of the text, since we don't actually want that in the final logo. We can just select the text and delete it.

Next, we'll remove the negative space from the inner part of the logo, because we want the inner part of the logo to be solid black. To do this, we'll need to use the path editing tool in the toolbar on the left. We'll just select the nodes for the inner paths and delete them.

Now let's make the pill shape around the outside. We'll use the rectangle tool and round the corners. I'll make the height of the rectangle 10m more than the diameter of the logo (70mm), and the width will be three times the diameter plus 10mm (190mm). The corners will be rounded with a radius in both directions of half the height of the rectangle (35mm), to produce an actual semicircle instead of just a rounded rectangle. We'll also position the rectangle so that the logo is centered on the left end's semicircle. Again, make sure that all the units are in millimeters. Additionally, it's useful to make the fill of the pill shape partially transparent, or to use only a stroke, so that we can see the logo underneath it. You can also reorder the objects after you make the pill the right size.

Finally, let's add the text. We should leave some space on the right end so that we can optionally add a hole for putting the badge on a keychain or something like that. We'll adjust the size to be pretty big but not too big.

Looking at the overall size, it's a little large. Let's make it smaller. Select everything and scale it proportionally, so that the height is 30mm. Make sure that the proportional resizing lock is enabled so that the width is scaled automatically in proportion to the height.

The design is now done, and we can save the file.